Question

Which of the following indicates that an exothermic reaction has taken place?

Answer 1

Answer:

The option B is correct option. Which is release of heat and/or light energy .

Explanation:

According to the definition of exothermic reaction :

An exothermic reaction is a chemical reaction that releases energy by light or heat.

From definition option B (release of heat and/or light energy) indicates that an exothermic reaction has taken place.

.

Answer 2

Answer: Option (B) is the correct answer.

Explanation:

An exothermic reaction is defined as the chemical reaction in which there occurs release of heat.

For example, $A + B \rightarrow AB + Heat$

In an exothermic reaction, energy of reactants is more than the energy of products.

Whereas an endothermic reaction is defined as a chemical reaction in which heat is absorbed by reactant molecules.

For example, $A + B + Heat \rightarrow AB$

In endothermic reaction, energy of reactant molecules is less than the energy of products.

Thus, we can conclude that release of heat and/or light energy indicates that an exothermic reaction has taken place.